  It is believed that magnetic activity on the Sun and solar-type stars are
tightly related to the dynamo process driven by the interaction between
rotation, convection, and magnetic field. However, the detailed mechanisms of
this process are still incompletely understood. Many questions remain
unanswered, e.g.: why some stars are more active than others?; why some stars
have a flat activity?; why is there a Maunder minimum?; are all the cycles
regular? A large number of prox- ies are typically used to study the magnetic
activity of stars as we cannot resolve stellar discs. Recently, it was shown
that asteroseismology can also be used to study stellar activity, making it an
even more powerful tool. If short cycles are not so un- common, we expect to
detect many of them with missions such as CoRoT, Kepler, and possibly the PLATO
mission. We will review some of the latest results obtained with spectroscopic
measurements. We will show how asteroseismology can help us to better
understand the complex process of dynamo and illustrate how the CoRoT and
Kepler missions are revolutionizing our knowledge on stellar activity. A new
window is being opened over our understanding of the magnetic variability of
stars.
