Any effect can be combined with any delivery, though some are much rarer than others. For example, it might be uncommon to see an Intoxicate effect channeled through a monster’s claws, but you will commonly find Intoxicate alchemy used among the adventuring community. There are many different effects, organized into different Effect Groups. These categorize the effects in two ways: they help describe how they’re defended against, and they give information about how to “fix” detrimental effects once someone’s been afflicted.
For example, the Weakness effect is in the Curse effect group. A Cleanse effect will remove all other Curse effects, so if you’ve been Weaknessed you might want to drink a Cleanse potion. Alternatively, a “Resist Curse” ability will let you prevent the Weakness from hitting you in the first place!
Unless otherwise specified, identical effects do not stack. No person may have a second copy of the same effect active at the same time, whether caused by a spell or alchemy or any other source. Therefore, you cannot have both a Poison Shield active from a spell and a Poison Shield active from an elixir.
You can, however, have similar effects active at the same time. For example, you might have both an Enhanced Blade and a Healing Blade spell active at the same time, since they are separate effects. If you are struck by an effect that you’re already under, the newest identical effect will always override the older ones. This resets the duration of the effect if it had a timed duration.
Example: Rendal is hit with a Paralysis gas thrown by a troll. Five minutes later, he is hit with a Paralysis spell from a goblin. Even though one was from a gas and one was from a spell, the effects are the same. Rendal will have to restart counting the five minute duration from the time he was hit by the spell.
Some effects simply represent various ways to get hurt. For most players, Normal, Silver, Magic, Flame, Lightning, Ice, and Stone will all simply do the stated amount of damage as normal; some monsters might be hurt differently by them (or even healed, such as hitting a Flame Elemental with Flame damage). Massive damage is explained in the Special Abilities section, since it is generally only used by NPCs.
Healing, Chaos, and Body are a little different. Healing will normally heal the Body Points of the living and harm the Undead; in both cases it bypasses Armor Points. Chaos is the opposite—it will heal the undead while harming the living, its foul energies striking straight past Armor Points directly to Body Points. For both of these, keep in mind the Carrier rules explained in the Calls section a little farther on; you can't get infinite healing for your friends from a Healing Blade spell!
Lastly, the Body damage type simply bypasses Armor Points entirely no matter what the target. It will also work when striking nearly any monster, as very few creatures are immune to the deadly strikes represented by this damage type.