The new metabolites xylobovatin, 19,20-epoxycytochalasin C, deacetyl-19,20-epoxy-cytochalasin C, xylobovide and 4,6,10,12-tridecatetraene-2,8-diol, and the known clonostachydiol and phaseolinon were isolated from the culture broth of the Ethiopian fungus Xylaria obovata. While the cytochalasins are cytotoxins, clonostachydiol is an anthelmintic, and phaseolinon and xylobovide show phytotoxic effects. The formation of these metabolites was studied and the more oxidized cytochalasins were found to be formed late in the fermentation process on moist sterile rice.