[en] The excitation functions of ¹²C(α,γ)¹⁶O and ²²Ne(α,n)²⁵Mg have been determined with a yet unequaled experimental sensitivity of 10^-11 b. From γ-angular distributions the S_E1-and S_E2-factors for ¹²C(α,γ)¹⁶O have been deduced and extrapolated into the range of helium burning temperatures using the R-matrix method. An improved reaction rate has been calculated: N_A<σν>=(7.9±2.5)x10^-15cm³(mols)^-1 at T₉ = 0.2. For a more precise extrapolation the excitation function has to be measured with better statistics. Therefore a new experiment on ¹²C(α,γ)¹⁶O with a better suited setup has been started recently. The accuracy of the ²²Ne(α,n)²⁵Mg reaction rate could be improved considerably compared to previous compilations: N_A<σν> = (0.88_-0.3^+2.6) x 10^-16cm³(mols)^-1 at T₉ = 0.2