Study population: Non-smoking healthy male volunteers, age 18-35 yrs Intervention: Subjects will be tested in a cross-over design in 2 separate sequential sessions, 2-4 weeks apart. A total of 12 subjects will be randomly assigned to one of two dosing groups in a 1:1 ratio: GTS-21 followed by Placebo n=6, Placebo followed by GTS-21 n=6. Subjects will receive 150mg GTS-21 or placebo orally tid 3 days before LPS injection and an oral dose of 150 mg GTS-21 or placebo the morning of the day of LPS administration (07:00 AM). Subjects will then receive an oral dose of 150 mg GTS-21 or placebo at 08:00 AM and another oral dose of 150 mg GTS-21 or placebo at 1 hour before LPS administration (t=0). Before LPS injection, prehydration will be performed by infusion of 1.5 L 2.5% glucose/0.45% saline solution in 1 hour. One hour after the last dose of GTS-21 or placebo, LPS derived from E coli O:113 will be injected (2 ng/kg iv in 1 minute). There will be a 14 day washout period for patients in all groups. The last group of subjects will be subjected to an identical dose of LPS and placebo at two different moments 2-4 weeks apart to obtain time controls.