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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 57–24–9

NIOSH REL: 0.15 mg/m3 TWA

Current OSHA PEL: 0.15 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.15 mg/m3 TWA

Description of substance: Colorless to white, odorless, crystalline solid.

LEL :. . . Unknown

Original (SCP) IDLH: 3 mg/m3

Basis for original (SCP) IDLH: No data on acute inhalation toxicity are available on which to base the IDLH for strychnine. The chosen IDLH, therefore, has been estimated from the statement by Gleason et al. [1969] that 30 mg by the oral route is usually a threat to an adult’s life [Witthaus 1911].

Short-term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value





Flury and Zernik 1935Moraillon & Pinault 1978

Moraillon & Pinault 1978

Prasad et al. 1981

Spector 1956

Ward & Crabtree 1942
















4.2 mg/m33.5 mg/m3

3.5 mg/m3

14 mg/m3

112 mg/m3

17 mg/m3

0.4 mg/m30.4 mg/m3

0.4 mg/m3

1.4 mg/m3

11 mg/m3

1.7 mg/m3

Human data: It has been reported that the probable lethal oral dose is 1.5 to 2 mg/kg [Gosselin et al. 1984]. [Note: An oral dose of 1.5 to 2 mg/kg is equivalent to a 70-kg worker being exposed to 70 to 93 mg/m3 for 30 minutes assuming a 50 liter per minute breathing rate and 100% absorption.]

Revised IDLH: 3 mg/m3 [Unchanged]Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for strychnine. However, based on acute oral toxicity data in humans [Gosselin et al. 1984], the original IDLH for strychnine (3 mg/m3) is not being revised at this time.


1. Flury F, Zernik F [1935]. Zusammenstellung der toxischen und letalen dosen für die gebräuchlichsten gifte und versuchstiere. Abder Hand Biol Arbeitsmethod 4:1289-1422 (in German).

2. Gleason MN, Gosselin RE, Hodge HC, Smith RP [1969]. Clinical toxicology of commercial products. 3rd ed. Baltimore, MD: Williams & Wilkins Company, pp. 214-217.

3. Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th ed. Baltimore, MD: Williams and Wilkins Company, pp. III-375 to III-376.

4. Moraillon R, Pinault L [1978]. Diagnostic et traitement d’intoxications courantes des carnivores. Rec Med Vet 154(2):137-150 (in French).

5. Prasad CR, Patnaik GK, Gupta RC, Anand N, Dhawan BN [1981]. Central nervous system stimulant activity of N-_3-chromene-3-carbonyl)-4 iminopyridine (compound 69/224). Indian J Exp Biol 19:1075-1076.

6. Spector WS [1956]. Handbook to toxicology. Vol. 1. Philadelphia, PA: W.B. Saunders Company, p. 286.

7. Ward JC, Crabtree DG [1942]. Strychnine X. Comparative accuracies of stomach tube and intraperitoneal injection methods of bioassay. J Am Pharm Assoc, Scientific Edition 31:113-115.

8. Witthaus RA [1911]. Manual of toxicology. 2nd ed. New York, NY: William Wood and Company, p. 1029.