Crassula arborescens (Mill.) Willd. subsp. Arborescens is widely used for the treatment of various ailments including diarrhoea, corns, epilepsy and as a purgative. However, no information exists in any literature to verify the acclaimed effectiveness of C. arborescens in the treatment of the various ailments. The study, therefore, intended to investigate the anticonvulsant activity of the leaf methanol extract of C. arborescens in mice. Acute toxicity study and phytochemical qualitative analysis of the plant extracts were also carried out. Chemically-induced convulsion methods were used to assess the anticonvulsant activity of C. arborescens. Standard methods were used for the acute toxicity study and phytochemical analysis of the chemical components of the plant extract. PTZ (pentylenetetrazole), bicuculline, picrotoxin, NMDLA (N-methyl-DL-aspartic acid) or strychnine produced tonic convulsions in all the mice used. Leaf methanol extract of Crassula arborescens, muscimol, phenobarbitone or diazepam significantly antagonised PTZ, bicuculline or picrotoxin-induced convulsion. C. arborescens or LY233053 significantly antagonised NMDLA-induced tonic convulsion. C. arborescens or phenobarbitone significantly antagonised strychnine-elicited tonic convulsion. Phenytoin or DMSO (dimethylsulfoxide) did not significantly affect the tonic convulsion produced by PTZ, bicuculline, picrotoxin, NMDLA or strychnine. The LD50 value obtained from intraperitoneal administration of C. arborescens was 781.6 mg/kg while that following oral administration of the plant extract was over 4,000 mg/kg. The phytochemical qualitative analysis done showed the presence of flavonoids, tannins, reducing sugar, saponins and triterpene steroids. The data obtained in the study show that the leaf methanol extract of Crassula arborescens has anticonvulsant activity which may be underpinned by GABAergic, glutaminergic and glycinergic mechanisms. The high LD50 value obtained following the oral administration of the plant extract shows that the leaf methanol extract is non-toxic to animals.