As there is no study on the combination adminstration of drugs with the use of INHG on animals, the author performed a series of experiments with guinea pigs using this drug in various combinations of SM and PAS, and studied which combination would be most effective from autopsy findings and cultnre of tuberculous bacilli in viscera. In addition, the author tried INAH, INHG, or IHMS of the INAH series combined with PAS, most frequently used clinically as basic drug for combination therapy, and studied the effectiveness on guinea pigs. The results are as follows: 1. It has been found that INHG used in combination with SM or PAS is more effective than INHG given singly. 2. Of the combinations mentioned above the combination of SM + INHG + PAS is most effective, followed by the combination of SM + INHG; and although the combination of INHG + PAS is still less effective, it is better than single adminstration of INHG. 3. Even in the PAS combinations of INHG, IHMS and INAH so long as the content of INAH in each combination is equal, two former ones are slightly less effective than the latter. But clinically these drugs can be given in a large dose, and hence there is a promising future for the effectiveness.