| Constitution can be raised with a Manual of Bodily Health in BG1. Some people like to play BG1 before playing BG2, and they import their characters. You can't play a half-orc in BG1 (unless you pay BG1-Tutu), but you can play a Dwarven Cleric, and I think a Dwarf can have 19 Constitution.
In Shadows of Amn, there are two ways to raise Constitution. The first is through the use of the spell Draw Upon Holy Might. It is available as a Bhaalspawn innate ability as well as a Priest spell. It only lasts one turn (I thought it lasted longer, but I just looked it up), so I'm not sure how many hit points it can help you recover. The second way is to take the evil path in the Fear test in Hell.
Some people like to play Throne of Bhaal after playing Shadows of Amn, so there are other ways to increase Constitution. The Obsidian Ioun Stone and Malla's Soul Stone both do it. I can't remember if there's a weapon that does it. You can also get an extra Wisdom point from the Machine of Lum the Mad, which is always part of my game plan. |