Some health-related things are an area where important advances could probably have happened earlier in principle: germ theory of disease, importance of sanitation, some relatively simple advances like antibiotics... All seem doable in principle relative to inventing a lot of 19th century industrial revolution devices.

ADDED: The Romans did apparently have some knowledge of antibiotics without presumably understanding the mechanisms or refining them. Per Wikipedia and other sources: "Antibiotics have been used since ancient times. Many civilizations used topical application of moldy bread, with many references to its beneficial effects arising from ancient Egypt, Nubia, China, Serbia, Greece, and Rome."