You probably mean fertilizer as medicine. What people suggest when you introduce a new plant is to wash the plant leaves with a mild soap, making sure you rinse it properly afterwards to get any pesticide off. Make sure ALL the soap is off too. Next you can re-pot/re-soil (take out the soil and add organic soil, non-fertilizer soil) or simply add large rocks over the soil in the pot so your Chameleon cannot accidentally eat the soil.