otrovati

1. to poison
   Neko je otrovao komšijinog psa. — Someone poisoned the neighbour's dog.
2. (otrovati se) to get food poisoning; to be poisoned
   Otrovao sam se ribom na moru. — I got food poisoning from fish at the seaside.
3. (of relations, mood) to poison; to spoil
   Ta svađa nam je otrovala celo leto. — That fight spoiled our whole summer.
4. (of water, soil, food) to poison; to contaminate with poison
   Otpad iz fabrike je otrovao vodu u reci. — Waste from the factory poisoned the water in the river.

The cause of poisoning goes in the instrumental: "otrovati se gljivama" (to be poisoned by mushrooms).