Lucy Wills, LRCP (10 May 1888 – 26 April 1964) was an English haematologist and physician researcher.
She conducted research in India in the late 1920s and early 1930s on macrocytic anaemia of pregnancy, a disease which is characterized by enlarged red blood cells and is life-threatening.Pregnant women in the tropics with inadequate diets are particularly susceptible.
Wills discovered a nutritional factor in yeast that both prevents and cures this disorder.
This component, the so-called 'Wills Factor', was subsequently shown to be folate, the naturally occurring form of folic acid.