counterirritant n : a medicine applied locally to produce superficial inflammation in order to reduce deeper inflammation

A counterirritant is a substance which creates inflammation in one location with the goal of lessening the inflammation in another location. They can be used as antipruritics. This strategy falls into the more general category of counterstimulation.

Capsaicin is an example of a counterirritant.

References

adjuvant, antacid, antidote, buffer, carminative, counteractant, counteractive, counteragent, emmenagogue, expectorant, hormone, maturative, neutralizer, nullifier, offset, preventative, preventive, prophylactic, remedy, vasodilator, vitamin