We study the constraints on the contribution of new physics in the form of scalar/pseudoscalar operators to the average forward-backward asymmetry AFB of muons in B→Kμ+μ- and the longitudinal polarization asymmetry ALP of muons in Bs→μ+μ-. We find that the maximum possible value of AFB allowed by the present upper bound on B(Bs→μ+μ-) is about 1% at 95% C.L. and hence will be very difficult to measure. On the other hand, the present bound on B(Bs→μ+μ-) fails to put any constraints on ALP, which can be as high as 100% even if B(Bs→μ+μ-) is close to its standard model prediction. The measurement of ALP will be a direct evidence for an extended Higgs sector, and combined with the branching ratio B(Bs→μ+μ-) it can even separate the new physics scalar and pseudoscalar contributions. © 2008 The American Physical Society.