OBJECTIVE The purpose of the present study was to evaluate the antidiarrheal effects and the phytochemical constituents of methanol extracts of some plants used traditionally in kingdom of Saudi Arabia using castor oil-induced diarrhea and gastrointestinal motility test using charcoal meal method were examined.METHODS The methanolic extracts were initially assayed for their effects in castor oil-induced diarrhea at different doses(250and 500mg·kg-1 followed by their evaluation on the peristaltic movements in charcoal meal test.RESULTS The results of the present study indicates that,administration of the following methanol plant extracts;Rhazya stricta,Heliotropium bacciferum,Tribulus longipetalus,Achillea fragrantissima,Artemisia herba alba,Haloxylon salicornicum,Plantago coronopus,Cyperus conglomerates,Hordeum distichon,Eragrostis poaeoides,Astragalus spinosus,Lepidium sativum seeds induced a higher percentages of inhibition of diarrhea.While,the administration of Rhanterium epapposum,Moltkiopsis ciliate,Lasiurus hirsutus,Deverra triradiata,Lycium shawii.Echinops spinosus,Echinops hussoni,and Prosopis farcta were the least efficacy.The antidiarrheal effects of these plants might be due to their high contents of flavonoids and tannins.CONCLUSION It could be concluded that,the remarkable antidiarrheal effects of these plants attest to their utility in a wide range of stats of diarrhea. OBJECTIVE The purpose of the present study was to evaluate the antidiarrheal effects and the phytochemical constituents of methanol extracts of some plants used traditionally in the kingdom of Saudi Arabia using castor oil-induced diarrhea and gastrointestinal motility test using charcoal meal method examined. METHODS The methanolic extracts were initially assayed for their effects in castor oil-induced diarrhea at different doses (250 and 500 mg · kg-1 followed by their evaluation on the peristaltic movements in charcoal meal test. RESULTS The results of the present study indicate that, administration of the following methanol plant extracts; Rhazya stricta, Heliotropium bacciferum, Tribulus longipetalus, Achillea fragrantissima, Artemisia herba alba, Haloxylon salicornicum, Plantago coronopus, Cyperus conglomerates, Hordeum distichon, Eragrostis poaeoides, Astragalus spinosus, Lepidium sativum seeds induced a higher percentages of inhibition of diarrhea. While, the administration of Rhanterium epapposu m, Moltkiopsis ciliate, Lasiurus hirsutus, Deverra triradiata, Lycium shawii. Echinops spinosus, and Echinops hussoni, and Prosopis farcta were the least efficacy. The antidiarrheal effects of these plants might be due to their high contents of flavonoids and tannins. CONCLUSION It could be said that, the remarkable antidiarrheal effects of these plants attest to their utility in a wide range of stats of diarrhea.