Vitamin A is a fat soluble vitamin crucial to cell health, vision, and reproductive health.  Because it is fat soluble it is possible to overdose on Vitamin A (compared to water soluble vitamins like C and E in which excesses can just be flushed out of your system).  Overdosing on Vitamin A can cause a number of problems including dry skin, osteoporosis, hair loss, liver damage and mental issues.  Vitamin A can also compete with and cancel out the more important vitamin D to a certain degree if overdosed on.  Wikipedia claims 75% of people in developed countries take in more than the RDA recommended limits of Vitamin A, but this sounds a little high. 

The right amount is up to debate, but probably should be between 10,000 to 15,000 IU's a day.

With this in mind, Vitamin A is still an important vitamin crucial for vision, bone health, memory, reproduction, and many other crucial bodily functions.

Natural sources of Vitamin A include liver, carrots, broccoli leaves, sweet potatoes, kale, butter, spinach, pumpkin, cantaloupe, eggs, apricots, papayas, mangos, peas, and broccoli.

For suppliments, you'll have to choose between the beta-carotene form and the palmitate version.  Beta-carotene tends to come from plants and is considered much less toxic (some argue you can't overdose on it) compared to the palmitate version which tends to come from animal products.

• Article on overdosing Vitamin A
  
• Study shows Vitamin A may help with Autism
  
• Study shows Vitamin A may help fight wrinkles
  
• Study shows Vitamin A helps fight malaria
  
• Vitamin A produces astonishing leukemia cure rate, even without chemotherapy
  

Please note that many of the cures on this website are in a state of incomplete progress. To simplify, I have created a 'best natural cures' page which I believe contain the most effective, non-drug, non-surgical cures available.