AIM To investigate the acute toxicity,phytochemical profile,antidiarrheal activity and mechanisms of action of Maytenus erythroxylon(M.erythroxylon)ethanol extract.METHODS A castor oil-induced diarrhea model was used to evaluate antidiarrheal activity.Intestinal transit and gastric emptying protocols were used to evaluate a possible antimotility effect.KATP channels,nitric oxide,presynapticα2-adrenergic and tissue adrenergic receptors were investigated to uncover antimotility mechanisms of action and castor oil-induced enteropooling to elucidate antisecretory mechanisms.RESULTS All tested doses of the extract(62.5,125,250 and 500 mg/kg)possessed antidiarrheal activity,with a significant decrease of the evacuation index.This activity is possibly related to a reduced gastric emptying(125,250 and 500 mg/kg)and to a decreased percentage of intestinal transit for all tested doses.That last effect seems to be modulated by nitric oxide,KATP channels and tissue adrenergic receptors.Besides,the extract also presented antisecretory effect due to a decrease of intestinal fluid accumulation.CONCLUSION The antidiarrheal effect of M.erythroxylon found in this study involves antimotility and antisecretory mechanisms that may be attributed to the chemical compounds found in this species:saponins,flavonoids,tannins,triterpenes and steroids. AIM To investigate the acute toxicity, phytochemical profile, antidiarrheal activity and mechanisms of action of Maytenus erythroxylon (M. erythroxylon) ethanol extract. METHODS A castor oil-induced diarrhea model was used to evaluate antidiarrheal activity. Intestinal transit and gastric emptying protocols were used to evaluate a possible antimotility effect. KATP channels, nitric oxide, presynaptic α2-adrenergic and tissue adrenergic receptors were investigated to uncover antimotility mechanisms of action and castor oil-induced enteropooling to elucidate antisecretory mechanisms .RESULTS All tested doses of the extract (62.5, 125, 250 and 500 mg / kg) possessed antidiarrheal activity, with a significant decrease of the evacuation index. This activity is possibly related to reduced gastric emptying (125,250 and 500 mg / kg) and to a decreased percentage of intestinal transit for all tested doses. That last effect seems to be modulated by nitric oxide, KATP channels and tissue adrenergic receptors .esides, th e extract also presented antisecretory effect due to a decrease of intestinal fluid accumulation. CONCLUSION The antidiarrheal effect of M. erythroxylon found in this study discloses antimotility and antisecretory mechanisms that may be attributed to the chemical compounds found in this species: saponins, flavonoids, tannins , triterpenes and steroids.