[his tone doesn't shift in the slightest as he moves to take the water from Sokka]

If the medicine alone isn't strong enough, there's another method that I've used before. One that will require moonlight.

[he sits on the floor beside his medicine chest-- fingers sorting and crushing dried leaves and stems with the deftness that only comes from years of experience.

After a moment, he sifts something into a small cup form his box that he's filled with the water, and presses it into Katara's hand]

This should take most of the pain away. I'm going to open one of the curtains, now.