In the present work there are described some spectral characteristics in the ultraviolet and infrared region under various environment conditions for a series of synthetic analogues of deoxyguanosine, substances possessing antiviral properties. The study is performed on the Acyclovir compounds and on its Na, K and Li salts, synthetized in Romania, in comparison with the similar product Zovirax, of the "Wellcome" firm (England), used in the clinical practice for several years. The results show a very marked resemblance of the spectral behavior for all these products, a conclusion confirmed by the similar biological effects in the herpetic infection.