Arriving at the tail end of the 1960s horror boom, Mad Doctor of Blood Island (directed by Eddie Romero and Gerardo de León) is a lurid, low-budget slice of Filipino-American exploitation that promised “horrors beyond belief!” but delivered more on schlock than shock. As the second entry in Romero’s Blood Island trilogy, it typifies the era’s appetite for gore, nudity, and pulp thrills—though not always in the most coherent fashion.

The film follows a ship-bound doctor, a reporter, and a young woman who arrive on a remote island plagued by strange deaths. It doesn’t take long before they encounter the titular “mad doctor,” played by Ronald Remy, whose gruesome experiments have spawned a chlorophyll-infused, acid-blooded mutant wandering the jungle. If that sounds deliciously absurd, it is—but Mad Doctor of Blood Island rarely rises above its own ridiculous premise.

Despite a promising atmosphere—lush jungle settings, a sweaty sense of doom, and some decent creature effects for the time—the film is hampered by a plodding pace, wooden dialogue, and a narrative that stumbles more often than it strides. There’s also a curiously uneven tone: part jungle adventure, part grotesque horror, and part softcore romp. The result is a film that doesn’t quite commit to any one direction, leaving much of the tension and horror flat.

Ronald Remy gives it a spirited go as the deranged doctor, and the creature design—goopy green and grotesque—has become a cult image in horror circles. But the characters are thin, the plotting slack, and the direction lacks urgency. Even the infamous “green blood” gimmick, which involved cinema-goers drinking a fluorescent concoction before the film began, can’t mask the film’s overall lack of bite.

The Prognosis:

Viewed today, Mad Doctor of Blood Island is more notable for its place in drive-in cinema history than for any cinematic merit. It remains a curious oddity—entertaining in stretches for B-movie aficionados, but ultimately more of a tropical misfire than a terrifying vacation.

• Saul Muerte