My 16 month old has a phlegmy cough. how do i treat it?

Cough in less than 2: It is best to not use cough and cough suppressants in children under 2. Most of them are not recommended for children under age 4. There are natural remedies like zarbees that contain honey and can be used in children greater than age 1. Also simply just try a cool humidifier and nasal saline drops for symptomatic relief.