Tonglen is Tibetan for 'giving and taking' (or sending and receiving), and refers to a meditation practice found in Tibetan Buddhism.

In the practice, one visualizes taking in the suffering of oneself and of others on the in-breath, and on the out-breath giving recognition, compassion, and succor to all sentient beings.] As such it is a training in altruism.

The function of the practice is to:

a) Reduce selfish attachment
b) Increase a sense of renunciation
C) Create positive karma by giving and helping
d) Develop and expand loving-kindness and bodhicitta