American government scientist John Ashley travels to a remote island in the Philippines to investigate rumors of strange deaths among the locals. There, he meets Dr. Lorca (Eddie Garcia), a scientist who has been experimenting on the populace using chlorophyll as a means of curing leukemia. Ashley soon learns that the experiments have instead created a green-blooded monster that is wreaking havoc on the villagers.
Though decidedly lacking on the technical side (directors Eddie Romero and Gerry de Leon's frequent use of zoom effects borders on nauseating), this Filipino-lensed mishmash of Weird Tales-style pulp adventure and '60s-era exploitation has a loopy charm that will be best appreciated by fans of low-budget horror. The special effects, while subpar by Hollywood standards, are appropriately gooey, and actresses Alicia Alonso and Angelique Pettyjohn provide sufficient eye candy in their softcore tryst with subdued lead (and co-producer) Ashley. Frequently screened on the drive-in circuit under a variety of titles, the film enjoyed some notoriety thanks to a pre-credit sequence devised by Independent-International head Sam Sherman, which urged viewers to drink "green blood" (in reality, a noxious mixture that made Sherman ill after tasting) in order to ward off the effects of Dr. Lorca's experiments. The monster, along with Ashley, Romero, and Garcia, would return in 1970's Beast of Blood.