Abstract: From May 1981 to August 1982, clinical observations were made on 8 cases of Dipetalonema perstans and 1 case of Loa loa microfilaremia returning from Equatorial Guinea and treated with a total dosage of 200mg/kg of furapyrimidone in 10 days. The daily dose was divided into 3 portions given orally. In cases of Dipetalonema perstans microfilaremia, the rates of clearance for blood microfilariae 1 day, 6 months and 14 months after the completion of treatment were 0, 60% (3/5) and 88% (7/8) respectively, and microfilariae reduction rates were 63.8%, 96.0% and 98.3%, while in the case of Loa loa, microfilaremia was negative immediately after treatment, but returned to positive 6 months later. The result showed that with the above-mentioned dosages, furapyrimidone is more effective against Dipetalonema perstans, especially against the adult worms, since the rates of clearance for blood microfilariae were higher with the time.