Previous work on the labour productivity effects of chronic illness ha
s not separated the effects of chronic illnesses from the effects of p
rescription medications taken to alleviate these conditions. Using nat
ionally representative observational data, this study estimates the pu
re effect of chronic illness, and the marginal effect of prescription
medicines, on labour productivity. As Americans continue to scrutinize
health care expenditures, such estimates will play an increasing role
in determining the allocation of resources for medical treatments. Es
timates are presented of the costs and benefits to employers of coveri
ng prescription medications for workers aged 18-64 years afflicted wit
h specific chronic illnesses. The effects of prescription medicines on
hourly wages and days lost from work are examined for four major chro
nic illnesses: hypertension, heart disease, non-insulin dependent (typ
e II) diabetes and depression. The net benefits to employers from havi
ng workers take prescription medicines for their chronic illnesses are
substantial. Assuming average compliance rates are achieved, net bene
fits to employers in 1987 amounted to $286 per hypertensive employee,
$633 per employee with heart disease; $822 per depressed employee, and
$1475 per type II diabetic employee under medication from a physician
. These estimated benefits accrue because prescription medications sub
stantially lower absenteeism among chronically ill workers.