Shakespeare's Sonnets: Like as to make our appetites more keen

Like as to make our appetites more keen,With eager compounds we our palate urge,As to prevent our maladies unseenWe sicken to shun sickness when we purge.Ev'n so being full of your ne'er cloying sweetness,To bitter sauces did I frame my feeding;And sick of welfare found a kind of meetnessTo be diseas'd ere that there was true needing.Thus policy in love t'anticipateThe ills that were not, grew to faults assuredAnd brought to medicine a healthful stateWhich, rank of goodness, would by ill be cured. But thence I learn and find the lesson true, Drugs poison him that so fell sick of you.