Twenty-three alkaloids have been identified in the root bark and stem bark of Strychnos johnsonii from Zaire. They are demethoxycarbonyl-3,14-dihydro-gambirtannine, angustine, dihydro-cycloakagerine, O-ethylakagerine, O-ethylakagerine lactone, dihydro decussine, normalindine, oxojanussine, tetrahydroalstonial, ajmalicinial, norepimalindine, norharman, harman, akagerine, akagerine lactone, janussines A and B, tetrahydro akagerine, demethoxycarbonyl-3,14,15,16,17,18-hexahydro-gambirtannine, dihydrocorynantheol, anthirine lactone, anthirine and isoanthirine. © 1987.