[Whiteblade111]

Hi, I'm new to Shadowrun, ( Been playing for a month ) and I've been making a chemist, and I have two questions.

One: In the players handbook it says that damage for a toxin is handled with a melee attack. That doesn't make any sense to me. Let's say I use Nega Venom, and I hit. Can someone explain how I'd deal damage from there?

Secondly: Can a Grenade Launcher fire any type of grenade? Or is it restricted to explosives? I mean can I load White Phosphorus in there and just go to town?

[Mantis]

The way a toxin works is usually a straight damage resistance roll. The method of delivery will determine the type of attack test used. If you try to apply a slap patch, then it is a melee attack as you cited. If you load it into capsule rounds then it is a ranged attack using whatever sort of gun is firing the capsule rounds. If you put it into a gas or splash grenade, then it becomes either a thrown weapon or heavy weapons test depending on how you deliver the grenade.
Whatever method delivers the toxin, the resistance test for the toxin itself will depend on the toxin. Narco-ject for example calls for a Body test against a 10S attack. Armour usually doesn't help with this.
Grenade launchers will fire mini grenades of whatever type you load into it. All grenade types are available as either thrown or mini grenades.