[en] Recent results are reported from the ARGUS and Crystal Ball experiments, operating at the DORIS II e⁺e^- storage ring at DESY. Addressing the problem with the branching ratios of the 1-prong τ decays a precise measurement of BR (τ^- → ν_τ π^-π⁰π⁰) = (6.6 ± 0.7 ± 1.7)% was performed. No evidence was found for the decay τ^- → ν_τπ^-η. This supports the absence of second class currents in τ decays. Many results concerning the weak interactions of b quarks have been obtained from the investigation of B meson decays. The exclusive semileptonic branching ratio BR (B⁰ → D^*-l⁺ν_l) = (7.0 ± 1.2 ± 1.9)% has been measured as well as the inclusive semileptonic branching ratio. First evidence for charmless B decays was found in the channels B⁺ → p anti pπ⁺ and B⁰ → p anti pπ⁺ π^- with the branching ratios BR (B⁺ → p anti pπ⁺) = (0.037 ± 0.013 ± 0.014)% and BR (B⁰ →p anti pπ⁺π^-) = (0.060 ± 0.020 ± 0.022)%. This yields a lower limit for /V_ub/V_cb/ ≥ 0.07. Finally B⁰ - anti B⁰ mixing was observed with three different analysis methods. The combined result for the mixing parameter is τ = 0.21 ± 0.08. This puts a serious constraint on some parameters of the standard model