Fluoride poisoning is known to cause a debilitating condition clinically referred to as Fluorisis. The present investigation on the experimental animal model has been carried out to collect information on the precise nature of fluoride action, with special reference to collagen biosynthesis. Rabbits subjected to Fluoride poisoning for varying time intervals were administered with carbon labelled proline. Both osseus and non-osseus tissues were analyzed to measure the rate of incorporation of labelled proline, and index for collagen biosynthesis. Part I of the article is dealing with 14C proline uptake by Hydrolyzed collagen (obtained by centrifugation at 5000 x g) and residual protein of tissues viz: Bone, Tendon, Muscle, Kidney cortex, Skin, Lung, Pinna and Trachea. Part II of the article is dealing with 14C proline uptake by different fraction of collagen Viz: collagenase digested fraction and separated by centrifugation at 9000 x g; native collagen fibril, acid soluble collagen, alkali soluble collagen and non-collagenous protein. The results obtained in Part I, suggest that in Fluoride poisoning collagen biosynthesis has been greatly impaired both in osseus and non-osseus tissues. This has been further confirmed by the results obtained in Part II of the investigation.