You must start off by having full life and stamina bars. Of course it helps having a good armor set. Bring Mega Demon and Mega Armor drugs, 5 flash bombs, 10 flashbugs, 10 bomb materials, a lot of Mega Potion, potion and honey. Shocktraps are a big help too.
Personally, I used the Khezu shocksword on the first encounter since thunder is it's weakness. The Poison Serpentbalde works too since it drains life when a monster is poisoned. Use flash bombs from a distance. As soon as the Tigrex gets stunned, the damage it can inflict will be lower but watch out when it spins. Hit it's head first (or you could go for the claws first). Keep stunning it with flash bombs. Once there's damage on either the head or the claws, you can go for the tail.
...oh, try to time your flashbombs when the Tigrex is about to roar. It's a good trick especially if you don't have Hear Protection or Ear Plugs.
Happy Tigrex Extermination!!!
Added by: warlord_from_hell Dec 23rd 2008, ID#2592