Saradomin brew

Saradomin brew is made by mixing toadflax and a crushed bird's nest in a vial of water, giving 180 Herblore experience. It requires level 81 Herblore. It is slightly lighter in colour than a normal strength potion.

Saradomin brew temporarily raises your Hitpoints by 15% (since it is a potion this means it is one of few ways to raise your Hitpoints above the normal maximum) and your Defence by 25% (better than a super defence potion if your Defence level is higher than 50). However, it also temporarily lowers your Strength, Attack, Magic and Ranged by 10%.

They heal the highest Hitpoints per inventory spot (if not counting the Unicorn Stallion's healing aura scroll and purple sweets, which can be stacked for approximately 4.2 billion hitpoints), and so, are often used in conjunction with Super restore potions in places such as in the TzHaar Fight Cave while attempting to obtain a Fire cape, high-levelled Bounty Hunting, or in Barrows runs, to decrease the number of bank trips required.

Production costs
The data in this table is based on the Grand Exchange prices of the Vial of water, herb, and secondary ingredient. It is accurate assuming all three items are bought off of the Grand Exchange and the resulting potion is sold afterwards.

Glitch
If you drink this first your Hitpoints go up by 25%. Next, drink a Zamorak brew. It deducts some Hitpoints. On your screen and everyone elses, it seems as you get damaged, but nothing happens on your health bar.

Trivia

 * There is no barbarian version of this potion so it cannot be made into a mix.