These are free Narcotics.

These provide 25 points of torpor over 2 seconds.

Regular Narcotics provide 40 torpor over 8 seconds.

Narcoberries are technically the best, simply because it's takes 12 seconds for torpor to be applied.

To calculate how many you need, Divide the max torpor of the dino you want to tame by 25 to determine how many mushrooms you will need to max the dinos torpor.

Hope it helps and happy taming!