They often are helpful, explaining to Mario and Luigi about how Bowser's body works. There are also rarer kinds that allow the brothers to save their game. They are usually orange or yellow, and Mario or Luigi must jump to hit and talk with them. There are usually a few Emoglobins found in each part of Bowser's body. They are known for replacing random nouns with the word "globin" (e.g. It's not globin science), and often putting "-ish" at the end of adjectives. In the Castilian Spanish translation they speak in a poem-like way in a very refined Spanish with rhymes.
There are also special Emoglobins located in the Toad Square and the Trash Pit. They are colored orange with green eyes. This type of globin secretes a sweat that restores both Mario and Luigi's HP and SP, similar to Recovery Blocks. A Toad runs a shop in Toad Square and sells the sweat for 10 coins, while the other is free to use.
There is also a kind of Emoglobin in the Challenge Node that resembles a Nintendo DS. The one who manages the Gauntlet uses the Bros.' memories to create stronger versions of the bosses that the Bros. have encountered through the game, and allows Mario and Luigi to fight these "X" bosses for a sizable fee.