  We discuss the exotic hadron structure and hadron-hadron interactions in view
of heavy ion collisions. First, we demonstrate that a hadronic molecule with a
large spatial size would be produced more abundantly in the coalescence model
compared with the statistical model result. Secondly, we constrain the
Lambda-Lambda interaction by using the recently measured Lambda-Lambda
correlation data. We find that the RHIC-STAR data favor the Lambda-Lambda
scattering parameters in the range 1/a_0 <= -0.8 fm^{-1} and r_{eff} >= 3 fm.
