The present study examined the effect of an extract from Sickingia wil
liamsii Standl. (Rubiaceae) on morphine withdrawal in vitro. The extra
ct of S. williamsii (50-100-250 mu g/mL organ bath) significantly and
in a concentration dependent manner reduced the morphine withdrawal. T
he results of the present study suggest that this extract may be a pot
ential antiaddictive agent.