This study was undertaken to determine the modulating effects of intramuscular administration of melatonin (MT)(1mg/ kg) and/or Tri-B (B 1 , B 6 and B 12 ) (20mg/kg) on body weight and some biochemical changes in rats induced by Epinephrine (Epi) injection. The data showed that MT and/or Tri-B treatment effectively improved the changes in malondialdehyde, lipid profile, blood sugar level and insulin. MT and/or Tri-B administration following Epi improved partially the decrease in body weight and liver glycogen levels. Tri B injection following Epi partialy improved all the tested parameters except malondialdehyde and blood sugar level that completely improved in stressed rats. It was evident that a combination of MT and vitamin B complex had protective actions and further it was better than either of them introduced alone in stressed rats. The possible interaction between MT and Tri B provided further support to MT synergistic actions with the aim of advocating MT and Tri B as a possible synergistic therapy.