These effects are also called non-stochastic or threshold-dependent effects.

Deterministic effects are due to high exposures. They appear early, above a certain threshold (about 1 sievert).

Examples for whole body exposure:

	from 1 to 2 sieverts: within 6 hours there is nausea, vomiting, headache and changes in blood chemistry, but the person usually recovers without treatment.
	from 2 to 5 sieverts: within 2 hours there is vomiting, bleeding and the bone marrow is affected but the person will recover provided a blood transfusion is given.
	over 5 sieverts: shock, the lungs and nervous system are affected, death is practically certain.

Knowledge of this dose-effect relationship is very useful for doctors because, in the first few hours following an accident, the dose received by the patient is not normally known; the observation of these early clinical signs will assist in the diagnosis.