OBJECTIVE We studied the toxicity of perfluorophenanthrene (PFP), used as short-, medium-, or long-term internal tamponading substance, on the rabbit choroid and retina. The aim was the check whether PFP is tolerated as a tamponade in the eye or damages the retina, and if any such damage is due to toxicity or to emulsification which may stimulate phagocytosis. METHODS Twenty-four right eyes of rabbits operated by vitrectomy were filled with 0.8-1 ml of PFP as retinal tamponading substance. Twelve eyes were operated by vitrectomy and filled with 0.8-1 ml of balanced salt solution as the control group. Direct and indirect ophthalmoscopy was done on the third and seventh day after surgery, then once a week. Enucleation, with histological and immunohistochemical examination, was done on the second day, then in the first, second, fourth and eighth weeks after surgery. CONCLUSIONS Histological examination showed progressive damage of the chorioretinal tissues right from the second week: the chorioretinal structure was completely altered from the eighth week. Immunohistochemical examinations showed that glia cells were involved in the inflammation consequent to internal tamponade with PFP.