This study was designed to evaluate the clinico-pathological and toxic effects associated with the intravenous administration formalin solution using 2 different concentrations (0.37% and 0.185%). Six, healthy adult female Holstein cows were used in the study. Whole blood samples were collected before (T0) and again at 15, 30, 60, and 120 minutes and at 24 hours after administration and placed in plain tubes and in EDTA and citrate containing tubes for the evaluation various hematology, serum biochemistry and some coagulation parameters including the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), platelets count, fibrinogen concentrations, and D-dimers. All cows tolerated well the administration of 0.37% and 0.185% formalin intravenously. There were no abnormal changes in the hematology and serum biochemistry profiles. In the coagulation profile, the administration of 0.37% formalin resulted in a significant decrease in APTT clotting times at 30, 60, and 120 minutes after administration. Thrombin time was also significantly decreased in this group at 15, 30, 60, and 120 minutes after administration. Platelet count was significantly increased at 60 and 120 minutes in this group. No significant changes were observed in PT values, fibrinogen concentrations and D-dimers at any time point. In cows administered 0.185% formalin, there was a significant decrease of APTT clotting times at 120 minute that remained at significantly lower levels at 24 hour after administration. Thrombin time was also significantly lower at 15, 30, and 60 minutes after administration. There was no significant difference in PT values, platelet counts, fibrinogen concentrations and D-dimers in this group at any time point. The results of this study showed that the intravenous administration of 0.37% formalin solution is safe with a pro coagulation effects in normal adult dairy cows. However, further clinical trials in actively bleeding animals are warranted before we safely recommend this treatment in the field.