Senzu Beans - will revive whoever eats one to full power nearly instantly. Here you can find out who ate them, when, and why. These beans are made by Korin in his tower and can also keep somone full for a very long time. If a Saiyan happens to eat one of these beans they will nearly double what there strength was before. Keep in mind this is only possible for a Saiyan to do. However, it's not something only a Senzu Bean can do Saiyan's happen to have a unique healing ability and will become much stronger once they have healed from a near death injury.
#1 - When Goku climbs Korin Tower in the Red Ribbon Army saga, he becomes extremely hungry from not eating for about 2 days, so Korin tosses him a Senzu Bean.
#2 - At Korin Tower, Goku uses another bean to heal himself from the fight with King Piccolo. This is when the true advantage of the Senzu Bean is first realized in the series.
#3 - After Goku fought Piccolo at the 23rd Budoukai, Yajirobe makes his first of many "Senzu deliveries". Goku uses a bean to heal from the intense fight and then for no apparent reason at all, gives Piccolo one. He later says that it was an act of pity, and "no matter how strong Piccolo becomes, I will always be one step ahead."
#4 - After Goku leaves Snake Way, he passes by Korin's tower. Korin throws him two beans, one of which he eats to recover from the harsh trip down Snake Way and the other he splits between Gohan and Krillin from the fight against Nappa.
#5 - After the fight against Vegeta, Goku is put in the hospital until he gets a Senzu Bean from Yajirobe. After he finished the Senzu Bean he grabs a bag full of them and heads to Namek. On his way to Namek Goku uses two Senzu beans because of his 100x gravity training and another when he hits himself with a Kamehameha.
#6 - When Goku arrives on Namek, he gives Gohan and Krillin half of a Senzu Bean to recover from their fight against Recoome. Goku then gives one to Vegeta who was also injured from the battle with Recoome, but only when he realizes that they are on the same side.
#7 - During the Android Saga Android #20 punches a hole through Yamcha's stomach nearly killing him. When Yamcha is taken out to Safety he is given a Senzu Bean restoring him to full health.
#8 - When Goku fights Android #19 everyone notices that Goku is weakening, because of this Krillin tosses him a bean. It has no effect, because the real problem was the heart virus which Future Trunks had said killed Goku in his time.
#9 - After Vegeta beats Android #19, he realizes that a lot of his power had been drained. Because of this he asks Krillin for a Senzu Bean (Krillin at this point has a whole bag of the Senzu Beans).
#10 - When Piccolo, Gohan, Tien, Krillin, and Vegeta are searching a desert for Android #20, #20 pulls a surprise attack on Piccolo and manages to take quite a bit of his energy. Piccolo recovers that energy with a Senzu Bean from Krillin.
#11 - After the fight with Android #17 and #18, Vegeta , Trunks , Piccolo , and Tien were all nearly unconscious. Krillin (still with the bag of Senzu Beans) gives each of them one.
#12 - Piccolo along with Tien were each beaten up by Cell. Piccolo was nearly killed and then blasted into the ocean and Tien was so weak after holding back Cell with all the Tri-Beams that he collapsed. After Tien was defenseless Cell began to kick him around, each were given a Senzu Bean by Goku.
#13 - When Trunks leaves Kami's lookout to follow Vegeta to Cell, Goku gives him two Senzu Beans that Korin had kept from before. Trunks uses the first one a while later to heal Krillin who had recklessly attacked Cell out of frustration that Android #18, whom he loved, had been absorbed. The second Senzu is used to heal Vegeta after his fight with Perfect Cell.
#14 - Korin rushes during the next ten days, to grow a few more Senzu Beans for Goku, and manages to give him the beans on his way to the Cell Games. However, the first bean used is Given from to Cell by Goku, after their fight. The purpose of this was to make sure the fight between Gohan and Cell would be fair.
#15 - After Goku, Piccolo, Vegeta, Trunks, Tien, Yamcha, and Krillin were badly injured from the Cell Juniors, Gohan got the bag from Cell (who had stolen them from Goku earlier when he tried to eat one and interfere in his fight vs. Gohan) and fed Krillin a bean. He then gave the bag to Krillen and told him to heal everyone else.
#16 - In the middle of the 25th Budoukai, Goku uses instant transmission to go to Korin Tower and retrieves a Senzu Bean for Videl, who had been badly beaten by Spopovitch in the tournament. When Goku gets back to the tournament he gives one of the three beans he had gotten from Korin to Gohan who immediately gives it to Videl.
#17 - When Gohan and Supreme Kai are about to go fight Dabura and Babidi, Goku tosses Gohan a Senzu Bean so he will be able to fight better (he was still a little wounded from the first time that he fought Dabura).
#18 - After Goku fights Majin Vegeta both warriors are badly wounded. Goku starts to pull out his bag of Senzu Beans deciding to split the last bean with Vegeta so they can both fight Fat Buu together. However, before he can do so, Vegeta knocks him unconcious from behind, steals and eats the last Senzu bean, and goes through the portal in Babidi's ship to face Fat Buu.