  We use recently released data on the positron-to-electron ratio in cosmic
rays from the AMS-02 experiment to constrain dark matter annihilation in the
Milky Way. Due to the yet unexplained positron excess, limits are generally
weaker than those obtained using other probes, especially gamma rays. This also
means that explaining the positron excess in terms of dark matter annihilation
is difficult. Only if very conservative assumptions on the dark matter
distribution in the Galactic Center region are adopted, it may be possible to
accommodate dark matter annihilating to leptons with a cross section above
10^-24 cm^3/sec. We comment on several theoretical mechanisms to explain such
large annihilation cross sections.
