In spite of all the people who want to make hay over Trayvon's pot habit, what set him off against Zimmerman was a bad combination of 17-year-old testosterone, teen-aged judgment, and a gigantic "Black Man in America" chip on his shoulder. The pot was probably the reason he went out for skittles and tea.
The autopsy report showed that St Skittle already had liver damage at age seventeen, the kind of damage caused by a particular thing called purple drank, concocted from Skittles, a particular flavored Ice Tea, and a cough medicine with a particular ingredient. There is some sort of synergistic effect in the combination. So no, St Skittles was more likely purchasing the ingredients for his favorite narcotic buzz which was killing his liver.
Not likely.
Skittles and watermelon tea are 2 of the 3 ingredients in "purple drank" or "purple lean". The third ingredient is cough syrup, either with codeine or Dextromethorphan (DM). Martin's Facebook page had an extensive discussion about the recipe.
Martin's liver autopsy showed signs of damage that could be caused by lean/drank abuse. DM abuse also can cause aggressive/paranoid behavior.