Knowledge, like physic, is more plague than profit, if it arrives too late.

Understand the thought

Meaning in plain English

Useful information may lose much of its value when it arrives after the decision or action it was needed for. Consider timing as well as accuracy when sharing what others need to know.

What the words are saying

The proverb compares late knowledge with a remedy delivered after the moment when it could help. Plague rather than profit expresses the frustration or burden of discovering too late what would have changed a choice. The comparison is figurative, not a rule about medical treatment or proof that late information can never help. It may still guide repair or a future decision. The useful concern is whether the people who need the information receive it while they can act on it. Sharing promptly should still preserve accuracy and necessary care, rather than treating an early guess as better than a responsible explanation.

Everyday example

A venue sends access requirements before booking is confirmed, giving an organiser time to choose suitable arrangements rather than discovering them after invitations go out.

When to use it

Use it when information needs to arrive before the action it is meant to guide.

Agent-assisted editorial interpretation. This explains the words; it does not by itself verify their author or earliest origin.