CHICAGO (AP) — Medical marijuana sales have begun in Illinois with patients flocking to state-licensed retail shops in five cities.

Among the first buyers Monday was Maggie Chatterton, a 25-year-old homemaker in central Illinois. She drove 20 miles to the Salveo Health & Wellness dispensary in Canton where doors opened around 9:30 a.m.

She says $385 an ounce is a fair price for a drug that she hopes will help her manage pain from a spine condition. She’s telling her 4-year-old son that marijuana is a natural medicine.

Five dispensaries plan to sell marijuana Monday. The others are in Addison, Marion, Mundelein and Quincy. Approximately 3,300 patients with Illinois-issued ID cards will be able to purchase medical cannabis.

Illinois is among 23 states with medical marijuana programs.