The pharmacokinetic behavior of S-allylcysteine (SAC), one of the biologically active transformation products from garlic, was investigated after oral administration to rats, mice, and dogs. SAC was rapidly and easily absorbed in the gastrointestinal tract and distributed mainly in plasma, liver, and kidney. The bioavailability was 98.2, 103.0, and 87.2% in rats, mice, and dogs, respectively. SAC was mainly excreted into urine in the N-acetyl form in rats; however, mice excreted both SAC and the N-acetyl form. The half-life of SAC was longer in dogs than in rats and mice.

F‐4, a protein fraction isolated from aged garlic extract strongly stimulates mice peritoneal macrophages in terms of glucose utilization and exhibits cytostatic activity in vitro. F‐4 also has a mitogenic activity on spleen cells. In vivo, F‐4 induced the stimulation of carbon clearance activity in mice. No obvious activities were observed in the low molecular fraction of aged garlic in these tests, but weak effects were found in the fructan fraction (F‐3).