| 1 | Red, Blue | Although small, its venomous barbs render this Pokémon dangerous. The female has smaller horns. |
| 1 | Yellow | A mild-mannered Pokémon that does not like to fight. Beware, its small horns secrete venom. |
| 1 | Stadium | Although small, it should be treated with caution because of its highly toxic thorns. The female has a small horn. |
| 2 | Gold | The poison hidden in its small horn is extremely potent. Even a tiny scratch can have fatal results. |
| 2 | Silver | Although not very combative, it will torment its foes with poison spikes if it is threatened in any way. |
| 2 | Crystal | Small and very docile, it protects itself with its small, poisonous horn when attacked. |
| 2 | Stadium 2 | The poison hidden in its small horn is extremely potent. Even a tiny scratch can have fatal results. |
| 3 | Ruby | Nidoran has barbs that secrete a powerful poison. They are thought to have developed as protection for this small-bodied Pokémon. When enraged, it releases a horrible toxin from its horn. |
| 3 | Sapphire | Its highly toxic barbs are thought to have developed as protection for this small-bodied Pokémon. When enraged, it releases a horrible toxin from its horn. |
| 3 | Emerald | Though small, it must be treated with caution because of its powerfully toxic barbs. The female has smaller horns. |
| 3 | FireRed | Although small, its venomous barbs render this Pokémon dangerous. The female has smaller horns. |
| 3 | LeafGreen | While it does not prefer to fight, even one drop of the poison it secretes from its barbs can be fatal. |
| 4 | Diamond, Pearl | While it does not prefer to fight, even one drop of the poison it secretes from its barbs can be fatal. |
| 4 | Platinum | The poison hidden in its small horn is extremely potent. Even a tiny scratch can have fatal results. |
| 4 | HeartGold | Although not very combative, it will torment its foes with poison spikes if it is threatened in any way. |
| 4 | SoulSilver | While it does not prefer to fight, even one drop of the poison it secretes from its barbs can be fatal. |
| 5 | Black | While it does not prefer to fight, even one drop of the poison it secretes from its barbs can be fatal. |
| 5 | White, Black 2 | While it does not prefer to fight, even one drop of the poison it secretes from barbs can be fatal. |
| 5 | White 2 | Although small, its venomous barbs render this Pokémon dangerous. The female has smaller horns. |
| 6 | X | Small and very docile, it protects itself with its small, poisonous horn when attacked. |
| 6 | Y, Omega Ruby, Alpha Sapphire | Nidoran♀ has barbs that secrete a powerful poison. They are thought to have developed as protection for this small-bodied Pokémon. When enraged, it releases a horrible toxin from its horn. |
| 7 | Let's Go, Pikachu!, Let's Go, Eevee! | A mild-mannered Pokémon that does not like to fight. Beware–its small horn secretes venom. |
