Twenty-month-old Swiss mice were allocated into three groups: (A) control; (B) infected group; and (C) infected but treated with 5 mg of the phytocompound MMT. Mice were infected intranasally with 30 μL of 75 HA viral units. MMT markedly blunted the nasal signs of virus infection and the febrile response. Formazan-positive cells, lung and plasma lipoperoxides, and TNF-α in lung tissue increased during viral infection, but improvement was seen in the MMT-treated group (P < 0.05). MMT also normalized SOD, catalase activities, and ascorbic acid and determined a significant decrease of lung but not nasal viral titer, although nasal inflammatory infiltrate dropped significantly. MMT has potential clinical applications with and has an excellent safety profile even in old animals.