A group of medical professionals and scientists are reduced to tiny size and introduced into the bloodstream of a vital international figure in order to remove a brain clot resulting from an assassination attempt. Inside this microscopic world, they face the body’s natural defenses and must navigate around crucial organs, all while racing against a one-hour deadline before returning to their normal size. Adding to the tension is the suspicion that someone aboard might be working against them. It's certainly a wild adventure. The film’s journey through the circulatory system and beyond is made remarkable by some truly creative special effects, which set it apart as one of the more visually impressive films of its era—it even earned Academy Awards for Best Colour Art Direction and Best Visual Effects, plus nominations for Best Cinematography, Best Editing, and Best Sound Effects. It’s undeniably a production with strong technical credentials. Adapted from a novel by Otto Klement and Jay Lewis Bixby, the story is both imaginative and completely captivating from a biological perspective, which helps to compensate for the somewhat subdued acting performances. But let's be honest, nobody’s watching this expecting brilliant portrayals. The goal is to be transported on a dangerous trip through the human body by director Richard Fleischer, and perhaps experience some suspense along the way. That objective is largely met, although the conclusion feels a bit hurried. Ultimately, it remains a peculiar but enjoyable film. 7.5/10

Source on TMDB