Theory of the Four Humours

The belief that health depended on a balance between four bodily fluids: blood, phlegm, yellow bile and black bile.

The belief that health depended on balancing four bodily fluids: blood, phlegm, yellow bile and black bile.

The historical belief that health depended on a balance of four bodily fluids: blood, phlegm, yellow bile and black bile.

An ancient explanation of health based on balancing four bodily fluids: blood, phlegm, yellow bile and black bile.

The belief that health depended on a balance of four bodily fluids: blood, phlegm, black bile and yellow bile.

The belief that health depended on a balance between four bodily substances: blood, phlegm, black bile and yellow bile.