This is the first in a series of posts detailing the locations of various potion ingredients in the game The Elder Scrolls:Oblivion IV. This is not a tutorial on gameplay or a walkthrough. If you need one of those check out OblivioWiki.
Alchemy is a magic skill under the attribute Intelligence. This means your intelligence affects how powerful your potions are and also means when you raise your alchemy level you are also potentually raising your intelligence attribute.
Alchemy is a great way to make money, especially at low level when you can't carry much loot. Alchemical ingredients are small and light weight so you can carry large amounts of them without becoming encumbered.
You can start gathering ingredients during the tutorial. Along the cave and tunnel floors you will find Cairn Bolate, Wisp Stalk and Stinkhorn mushrooms. You get rat meat from the rats you kill and a mort flesh from the zombie. I also picked up tomatoes, lettuce and cheese wedges off the floor. There is a goblin in the tunnels with a mortar and pestle. Pick the mortar and pestle up as you can't make potions without it.
Check the kegs, chests and goblins in the latter half of the tutorial. I picked up flour, some cheese wheels and a garlic but it seems to be random.
Once you are outside the sewers you can pick up Clouded Funnel Cap and Green Stain Cap mushrooms just to the left of the sewer entrance. You can also pick off a few mud crabs for crab meat. Unless you took Alchemy as a major skill, all you will be able to see is one potion effect. Go ahead and make some potions. Most of them will be damage fatigue or restore fatigue but don't worry about it. The merchants will buy them whatever they are. Don't worry about saving any ingredients, with the exception of garlic all of them are fairly easy to find.
(I always save my garlic. If you catch porphyric hemophilia (vampirism) and can't reach a temple or take a cure disease potion in time you may need the garlic for a quest to de-vamp yourself.)
If you reach level twenty five while potion making you get two effects available for each ingredient. This enables you to make detect life, damage and restore health, night eye and a few other potions handy at the lower levels. If you still haven't, don't worry. It should only take a few more potions before you gain apprentice.
After you make your potions, (and do the gear checking-weapon/spell choosing thing) head off into the water toward the large ruins or visible glow of campfires. (depending on time of day) Watch out for slaughterfish (yay scales - good for waterbreathing) and crabs. You will need to defeat the bandits camping outside the ruin but once you do you can search the area for ingredients.
The bandits have an assortment of food and some garlic. They also have quite a few arrows and fur armor if you missed picking those up during the tutorial. Scattered aound the area are broken casks with food and a little bit of searching will turn up Foxglove, Monkshood and Bergamot. On the west side of the ruins is a small dock. After you gleefully loot the chests, step off and hunt around the rocks at the water's edge. You should find a big glowing plant. This is Nirnroot and you will need a lot of them for a quest later in the game. You can also pick off a few more crabs for the meat.
This is the point in my games where I start to get close to my max carry abilities so I usually cross the water back to the sewer entrance, then climb up the eastern side of the hill to the city bridge. This leads to the Market District and that is a subject for another post.