The 中 in 中毒 is pronounced zhòng (4th tone), not zhōng (1st tone). When 中 means 'to be hit/struck by something,' it uses the 4th tone: 中毒, 中奖 (win a prize), 中招 (fall for a trick).
usage
食物中毒 (food poisoning) is the most common compound. In modern slang, 中毒 can also mean 'addicted' - 我中毒了 (I'm hooked/addicted).
