positive semidefinite matrices returning negative eigen values with eig function

I have asymmetric, positive semidefinite matrix A. Theoretically, all its eigenvalues should be greater than or equal to zero. But when I use eig function,some of the resultant eigenvalues are negative in sign.I can use svd too and when I used SVD, the eigen values turn out to be positive. I need the eigenvectors too. Can I just take the absolute values of the eigenvalues obtained from the eig command and process further.