Active Effect

An active affect is a current affect that is on the player.

He/she will receive the benefits or disadvantages of a potion, spell, enchants, poison, etc...

An active effect may vary in the ammount of time that it last, meaning that it could could last for two seconds or one whole day. (Although I do not know of one that lasts 24 hours.)

Effects:

Potions: Potions can have many uses. They can boost or add magicka, stamina, or health, improve skills for a temporary ammount of time, and can also provide the effects of anything from invisibility to waterbreathing.

Poisons:

Poisons are a variation of potions. They can cause slowness, they can cause drain to magicka health and stamina, and many more effects. In my personal experience, I have found that not many NPC's actually use poison, they mostly use spells and enchants.

Enchantments:

Enchantments can have most of the abilities of potions, except for that they are permanent.

The only enchantments that you can not compare with a potion is additional affects such as invisibility, or waterbreathing. (They would be overpowered.)

Spells:

Spells are another example of making active effects. On yourself, you can heal yourself, or use secondary abilities such as muffle, clairvoiyance, or invisibility, and many more.

NPC's can use spells on you that do damage or have harmful effects, such as the slowing effect.

That was all of the active effects I know of, but if you have any corrections, or anything new, please edit, this is kind of a stub of an article.