The chemical investigation of the ethanol/water (7:3) extract of the roots of Detarium microcarpum (Fabaceae) led to the isolation of one new labdane diterpenoid, microcarpin ( 1 ) and one new ceramide derivative, microcarpamide ( 2 ), along with eight known secondary metabolites ( 3–10 ) including, 5-(carboxymethyl)-5,6,8a-trimethyl-3,4,4a,5,6,7,8,8a-octahydronaphthalene-1-carboxylic acid ( 3 ), microcarposide ( 4 ), rhinocerotinoic acid ( 5 ), 1,7-dihydroxy-6-methylxanthone ( 6 ), ursolic acid ( 7 ), 3 β ,23-dihydroxylup-20(29)-en-28-oic acid ( 8 ), alphitolic acid ( 9 ), and stigmasterol glucoside ( 10 ). The structures of these compounds were elucidated based on their spectroscopic data. Although compounds 3 and 4 are known, their crystalline structures are reported here for the first time. These compounds were evaluated in vitro for their antisalmonella activity. The results obtained showed that, microcarpamide ( 2 ), microcarposide ( 4 ), and rhinocerotinoic acid ( 5 ) were moderately active against three salmonella strains: Salmonella typhi , Salmonella enteritidis and Salmonella typhimirium , with minimum inhibition concentration values of 76.7 and 153.5 μM.