The results of the treatment of some infectious diseases with laurilsulphate tetracycline a long acting tetracycline, are reported 16 patients suffering from several infectious diseases were given 5 to 15 mg/kg/day parenterally once or twice a day for four to 14 days (according to the type and severity of the diseases). 14 children considered as Streptococcus carriers were given 10 mg/ kg/day orally for 10 days. Tolerance to the drug was good. Most of the patients complained of a slight pain on the site of injection. One patient with leptospirosis had a generalized cutaneous rash which could also been caused by the disease. The authors conclude that laurilsulphate tetracycline has the same spectrum of other tetracylines, with the possibility of being administered at longer intervals.