The antituberculous activity of isoniazid used alone or in combination with streptomycin or para-aminosalicylic acid (PAS) has been established.’ One of the most favorable properties of isoniazid is the low incidence of significant toxicity resulting from its use when doses of 3 to 5 mg. per kilogram per day are administered. Some of the reactions reported include toxic psychosis, convulsions, ...
