Following claims of anthelmintic activity of Cereus jamacaru DC (Cactaceae) by a commercial
farmer, in vivo studies were conducted to determine the possible direct anthelmintic effects of the
plant on ovine gastrointestinal nematodes. Eighteen sheep were infected with 4000 Haemonchus
contortus and 6000 Trichostrongylus colubriformis larvae given in three divided doses over a
period of three days. Once the infections were patent, the sheep were allocated to three groups
and were drenched once a week for six weeks with fresh blended C. jamacaru plant material at a
single (32.3 g/sheep) or double dose (64.6 g/sheep) or they remained as undrenched controls.
Faeces were collected from individual animals on the day of treatment and three days thereafter
on a weekly basis for seven weeks for faecal egg count. While there were no statistically
significant differences in the egg counts between the groups, a double dose of C. jamacaru was
effective in reducing the egg counts in the sheep by 18-65% over the 49 days of the experiment.
Given that all animals remained in good health throughout the course of the experiment, with no
adverse events occurring during the study, further experiments using higher doses or
administering the plant material for a longer period of time than in the present study would be