Phaneropsolidae is one of the digenean intestinal parasites of reptiles, birds, and mammals. To 
cease its life cycle, some cercariacidal drugs were used, such as praziquantel and albendazole. 
The intermediate host, a freshwater snail, Lanistes carinatus, was collected from Al-Inaniyyah 
village in the north-east of Damietta Governorate, Egypt. Phaneropsolus praomidis cercariae 
(xiphidiocercaria type) were harvested by exposing snails to strong artificial illumination. Lethal 
effect of both drugs, they were tested on the living cercariae of Phaneropsolus praomidis. The 
emerging cercariae were divided into three groups, the first group (group 1), which is the control 
group, contained 40 cercariae, the second group (group 2); and the third group (group 3) were to 
test the effect of praziquantel and albendazole, respectively, on the vitality of cercariae. The 
LC50 and LC95 of praziquantel against the present cercariae of Phaneropsolus in group 2 were 
0.03 and 0.21 ppm, respectively. While in group 3, the LC50 and LC95 of albendazole were 0.87 
and 2.7 ppm, respectively. Praziquantel has a more devasting effect against the treated cercariae 
of Phaneropsolus praomidis compared with albendazole. The ultrastructural changes using SEM 
that occurred on the tegumental surface of the treated cercariae with the two drugs were also 
observed compared to the untreated cercariae. The untreated cercariae have a pentagonal-shaped 
body with a long tail. In comparisons, cercariae treated with both drugs lost all healthy 
morphological features, but in varying degrees and effects between the two drugs.