Seven schizophrenics and three patients with severe character disorders who were refractory to usual psychotropic medication were treated with fluphenazine hydrochloride 300 to 1,200 mg/day for two to nine months. Five schizophrenics had good-to-excellent responses, one had questionable improvement, and one became increasingly psychotic. All three patients with severe character disorders had good-to-excellent responses. The most frequent side effect was mild sedation and lethargy. Other side effects were minor and transient. This confirms the French observation that at low dosage (up to 25 mg/day) the predominant side effects are extrapyramidal while at high dose (100 to 1,200 mg/day), the most frequent side effect is mild sedation. These observations of the therapeutic efficacy of very high dosage fluphenazine are preliminary and should be reproduced in a double-blind study.