oh boy... that is an in depth question, due to some medicinal properties being better drawn out by alcohol, some by vinegar,glycerins, some by oils...etc. You know, I'd get a book like Richo Cech's "Making Herbal Medicine" before you jump into it... in fact read up on it, there are a lot of good herbals. Richo's book is very good and explains a lot.

Fruit vinegars and cordials are made the way you describe: infuse the fruit in vinegar or alcohol (for a cordial add sugar), let sit for a few weeks, strain and bottle. Due to the risk of bacterial contaimination, refrigeration is recommended even with alcohol.

If the fruit is watery like canteloupe, you may or may not get a good result. I make raspberry vinegar, basil vinegar and tarragon vinegar and raspberry cordial every year and have had good results with sour cherry cordial too.

Flavoured oils for salad can be made by adding herbs, garlic, hot peppers etc to oil. Again, refrigerate for safety.

As to medicinal herbs, you will need to consult a medicinal herb book for advice on whether to use oil or alcohol. Should be available in your public library.

It's far easier to just buy the scented oils and extracts.

Extracting takes time, good technique, and the proper equipment.

So you wanna make pepper extract? HereÂs how.
WhatÂs really gonna happen will be the extraction of capsaicin from your hot peppers with an organic solvent.
Capsaicin is an oleoresin found in many plants, principally in peppers, or "capsicums". The hotter the pepper, the more capsaicin present. To separate the capsaicin (the hot stuff) from the pepper (the other stuff), you can use a very common and relatively inexpensive organic solvent known as ethanol, a.k.a. pure grain alcohol, or even plain old vodka.
The method I use is very simple and very effective. First I get a quantity of dried peppers of choice (I use habaneras because I like their taste), and grind them coarsely. I place the ground peppers in a sealable jar and add enough grain alcohol to just cover. I put the lid securely on the jar and give it a good shake, and put it in the fridge. Every time I think about it, I give the jar another good shake.
After 3 or 4 days, I set up another sealable jar with a funnel. Inside the funnel I place a coffee filter. Then I pour the peppers that have been soaking in the alcohol into the filter, and let them drain completely. I seal the second jar containing the pepper extract and alcohol and put it in the fridge. Then I return the drained ground peppers to the first jar, cover again with alcohol, seal, shake and return to the fridge remembering to shake occasionally for another 3 or 4 days. Then I repeat the filtering process, reserving the filtered extract in the second jar as before. To be on the safe side, I flush the now spent ground peppers down the toilet and place their jar in the trash.
The filtered alcohol contains a considerable amount of capsaicin and you can taste it. But, PLEASE do it this way until youÂre sure you can handle the heat!!!!
Dip the mere tip of a toothpick into the liquid. Shake it off. And only then, place the mere tip of the toothpick to your tongue. DONÂT LICK IT !!!!! Do this only once, because it may take several seconds for you to realize the heat. If it is too hot , DONÂT DRINK WATER! Drink milk, eat some cheese or even eat some sugar. BUT, DONÂT DRINK WATER!
Pour the strained liquid into something like a glass pie pan, cover with cheese cloth, and set in a dark place to allow the alcohol to evaporate. After the alcohol evaporates, you will be left with capsaicin oil. This is VERY, VERY HOT STUFF! ItÂs dangerous if misused.