728. Rad Counters
In short
Rad counters (Fallout): player counters with a built-in trigger — at the beginning of your precombat main phase you mill as many cards as you have rad counters, lose 1 life per nonland card among them and remove that many counters. Radiation slowly wears off.
Informal summary — the official English text below is authoritative.
728.1.Rad counters are a kind of counter a player can have (see rule 122, “Counters”). There is an inherent triggered ability associated with rad counters. This ability has no source and is controlled by the active player. This is an exception to rule 113.8. The full text of this ability is “At the beginning of each player’s precombat main phase, if that player has one or more rad counters, that player mills a number of cards equal to the number of rad counters they have. For each nonland card milled this way, that player loses 1 life and removes one rad counter from themselves.”
728.1aA card that refers to life loss “from radiation” refers to life lost as a result of the triggered ability associated with rad counters.
Source: Wizards of the Coast, Magic: The Gathering Comprehensive Rules. Unofficial presentation under the Fan Content Policy. Rules effective as of Sep 25, 2026