  We present a new Fortran code to calculate the scalar one-loop four-point
integral with complex internal masses, based on the method of 't Hooft and
Veltman. The code is applicable when the external momenta fulfill a certain
physical condition. In particular it holds if one of the external momenta or a
sum of them is timelike or lightlike and therefore covers all physical
processes at colliders. All the special cases related to massless external
particles are treated separately. Some technical issues related to numerical
evaluation and Landau singularities are discussed.
