Castor oil

Castor oil	Last updated: 24/08/2025
(Also known as: Ricinus oil; Tangantangan oil; Phorbyol; Trypsin complex)

Hazard alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.

Environmental fate	Ecotoxicity	Human health
		Human health Moderate alert: Reproduction/development effects

GENERAL INFORMATION

Description

Castor oil is a triglyceride that can be used as a general garden non-toxic pesticide used to repel a range of garden pests. Ricinoleic acid is considered to be the bioactive component,

Example pests controlled

Voles; Moles; Mice; Rats; Squirrels; Gophers; Armadillos; Other burrowing vertebrate pests

Example applications

Crops; Houseplants; Lawns

Efficacy & activity

Appearance and life cycle

Taxonomic classification

Class: Magnoliopsida; Order: Malpighiales; Family: Euphorbiaceae

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Not applicable

Date EC 1107/2009 inclusion expires

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

Not applicable

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece

ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg

LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway

Additional information

Known to be also used in the following countries

USA

Chemical structure

Isomerism

Castor oil itself does not exhibit classical isomerism as a single compound, because it is a complex mixture of triglycerides, primarily composed of ricinoleic acid esters. However, isomerism becomes relevant when castor oil is chemically modified, such as in dehydrated castor oil, which contains fatty acid isomers.

Chemical formula

C₅₇H₁₀₄O₉

Canonical SMILES

CCCCCCC(CC=CCCCCCCCC(=O)OCC(COC(=O)CCCCCCCC=CCC(CCCCCC)O)OC(=O)CCCCCCCC=CCC(CCCCCC)O)O

Isomeric SMILES

CCCCCCC(O)C/C=C\CCCCCCCC(=O)OCC(OC(=O)CCCCCCC/C=C\CC(O)CCCCCC)COC(=O)CCCCCCC/C=C\CC(O)CCCCCC

International Chemical Identifier key (InChIKey)

ZEMPKEQAKRGZGQ-AAKVHIHISA-N

International Chemical Identifier (InChI)

InChI=1S/C57H104O9/c1-4-7-10-31-40-51(58)43-34-25-19-13-16-22-28-37-46-55(61)64-49-54(66-57(63)48-39-30-24-18-15-21-27-36-45-53(60)42-33-12-9-6-3)50-65-56(62)47-38-29-23-17-14-20-26-35-44-52(59)41-32-11-8-5-2/h25-27,34-36,51-54,58-60H,4-24,28-33,37-50H2,1-3H3/b34-25-,35-26-,36-27-

2D structure diagram/image available?

General status

Biopesticide type

Semiochemical; Other substance

Other bioactivity & uses

Adjuvant; Food Additive

Substance groups

Plant-derived substance; Plant oil

Minimum active substance purity

Known relevant impurities

Linoleic acid <4%; Oleic acid <3%; Stearic acid <1%

Substance origin

Natural; Complex mixture

Mode of action

Non-toxic mode of action. Odorant repellent. Suffocation for most insect pests with some antifeedant properties, and asphyxiation for rodents

Substance source

Castor oil originates from the seeds of the castor plant (Ricinus communis), which is native to the Ethiopian region of tropical East Africa

Uses

Crop protection

Target pests

Voles; Moles; Mice; Rats; Squirrels; Gophers; Armadillos; Other burrowing vertebrate pests

Target host

Crops; Houseplants; Lawns

Farming system suitability

CAS RN

8001-79-4

Alternative/old CAS RN

68956-68-3

EC number

232-293-8

CIPAC number

US EPA chemical code

031608

PubChem CID

14030006

Molecular mass

933.4

PIN (Preferred Identification Name)

2,3-bis[[(Z)-12-hydroxyoctadec-9-enoyl]oxy]propyl (Z)-12-hydroxyoctadec-9-enoate

IUPAC name

2,3-bis[[(Z)-12-hydroxyoctadec-9-enoyl]oxy]propyl (Z)-12-hydroxyoctadec-9-enoate

CAS name

Forever chemical

Other status information

FEMA=2263; USEPA minimum risk pesticide

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

A pale-yellow or almost colorless transparent viscous liquid with a faint mild odor and nauseating taste. It is comprised mainly of fatty acids (~98%) and lipids.

Related substances & organisms

fatty acids (generic C7-C18)

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1994, first registered USA

Example manufacturers & suppliers of products using this active now or historically

HJ Baker & Co.
Spectrum

Example products using this active

Caster oil

Formulation and application details

Sold as the pure oil or as emulsifiable concentrates

Commercial production

The oil is pressed from the castor bean Ricinus communis. Alternatively, the oil may be solvent extracted using heptane or hexane

Impact on climate of production and use

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Miscible

Methanol

Miscible

Ethanol

Miscible

Chloroform

Melting point (°C)

-10

Freezing Pt

Boiling point (°C)

313

Degradation point (°C)

Flashpoint (°C)

229

Octanol-water partition coefficient at pH 7, 20 °C

Log P

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

0.962

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Caster oil has laxative properties
Slightly corrosive to skin
Castor beans contain ricin which is highly toxic
Possible liver toxin at high doses
May cause a significant increase in prostaglandin E2 in females

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Will emit irritating and toxic gases when heated to decomposition or combusted

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

Highly stable.

TRANSLATIONS

Language

Name

English

castor oil

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	24/08/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242