At the start of the game, you’re wearing a T-shirt and cargo pants, neither of which were chosen or designed for the purpose of guerrilla warfare. In order to survive, you need to construct your own syringe kits, ammunition bags, rucksacks, and even medication out of the flora and fauna of Rook Island. You’ll need to hunt and explore to find the hides, skins, and plants you need.
Containers
The smaller containers can be fashioned out of the hides of commonly available animals, many of which are native to the hills around Amanaki Village. Boars, pigs, and goats are easy to find around Heron’s Point, the pirates’ guard dogs and the rabid hounds in the countryside can both be skinned, and even deer show up as you travel to the northeast.
One of the basic features of your in-game map is that it has labels that indicate what animals are native to a given region in the island. This is a useful guideline, but it’s not a hard-and-fast guarantee.
The fourth and final upgrade for most of your containers, except for weapon holsters and rocket packs, requires the skin of a unique animal, which only appears as part of a “Path of the Hunter” mission. You unlock these missions by securing various outposts throughout Rook Island.
Syringes
There are five kinds of syringes in Far Cry 3 . Medical syringes involve healing from trauma, and contain Green Leaves; Exploration syringes help you reach new locations or survive longer in the wilderness, and require Blue Leaves; Combat syringes specifically affect your ability to inflict or withstand damage, and are made with Crimson Leaves; and Hunting syringes use Amber Leaves and boost your effectiveness against members of the animal kingdom. Finally, Special syringes contain White Leaves, require a massive amount of ingredients, and confer short-term, powerful buffs.
Naturally, you will be jamming Medical syringes into yourself at a ridiculous rate throughout most of the game. Green Leaves are common across most of the North Island and are easy to stock up on, and you’d do well to have at least three Medical syringes on you at any given time. It’s the first recipe you learn, the first one you make, and the most important of the lot.
It will be quite a while before you unlock any of the crafting recipes for Special syringes, and you can find White Leaves well before that point. They simply take up space if you pick them up before then, and can be safely disregarded until such time as they have a use.