| 100% | OPIUM | 5 | Drug that caused a 1839-42 war |
| 46% | LSD | 3 | Drug that causes trips |
| 45% | OPIUM | 5 | Cause of an 1839-42 war |
| 44% | CATALYST | 8 | Thing that causes a change |
| 44% | STAMPTAX | 8 | Colonial grievance that was a cause of the Revolutionary War |
| 43% | THEWASPS | 8 | Aristophanes play that caused a buzz |
| 43% | GASSER | 6 | Joke that causes a belly laugh |
| 43% | POX | 3 | Infectious disease that causes a rash |
| 43% | STIMULI | 7 | Things that cause a particular reaction |
| 43% | IVY | 3 | Poison ___ (plant that causes a rash) |
| 43% | POX | 3 | Disease that causes a skin rash |
| 43% | SUMAC | 5 | Poison ___ (plant that causes a rash) |
| 42% | TNT | 3 | Stick that causes a big bang: Abbr. |
| 42% | FLEA | 4 | Insect that causes a dog to scratch |
| 42% | RED | 3 | Color that causes a bull to charge |
| 42% | OPIATE | 6 | Drug that's a downer |
| 42% | DIURETIC | 8 | Drug that causes an increase in the flow of urine |
| 42% | SUMAC | 5 | Poison ___ (plant that causes a rash when touched) |
| 42% | ALLERGEN | 8 | Thing that causes a reaction, like pollen, gluten |
| 42% | TNT | 3 | Stuff that causes a building to implode: Abbr. |
| 42% | NETTLE | 6 | Stinging ___ (plant that causes a rash when touched) |
| 41% | EVERGIVEN | 9 | Container ship that caused a blockage in the Suez |
| 41% | POGO | 4 | Stick that causes a spring in one's step? |
| 41% | URUSHIOL | 8 | The oil in poison ivy that causes a rash |
| 41% | OPIUM | 5 | Drug that's smoked in a pipe |
| 40% | PEA | 3 | Vegetable that caused a princess agony, in a fairy tale |
| 40% | STRANGERTHINGS | 14 | Netflix series that caused a 2017 surge in Eggo sales |
| 40% | SKIP | 4 | Uno card that causes a player to lose a turn |
| 40% | CROUP | 5 | Infection that causes a rough-sounding cough, usually in children |
| 40% | LSD | 3 | Drug that can cause an acid trip: Abbr. |