The present experiment was conducted to compare the therapeutic effects of laser irradiation on Kyo-So Hyul with those of antidisrrheal drugs gentamycin, berberine and sulfisomidine for 173 piglets with diarrhea as major symptoms. The results obtained were as follows; antidiarrheal drugs were effective in fifty nine (78%) of seventy six piglets and ineffective in seventeen (22%) of seventy six piglets. Laser irradiation on the Kyo-So Hyul were proved as effective in eighty eight (91%) of ninety seven piglets and invalid in nine (9%) of ninety seven piglets.