Wilsonian approach to the interaction <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>ϕ</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo stretchy="false">(</mml:mo><mml:mi>i</mml:mi><mml:mi>ϕ</mml:mi><mml:msup><mml:mo stretchy="false">)</mml:mo><mml:mi>ϵ</mml:mi></mml:msup></mml:math>

We study the renormalisation of non-Hermitian $\mathcal{P}\mathcal{T}$-symmetric scalar field theory with interaction $\phi^2(i\phi)^\varepsilon$ using Wilsonian approach and without any expansion in $\varepsilon$. Specifically, we solve Wetterich equation local potential approximation, both ultraviolet regime loop expansion. calculate scale-dependent effective its infrared limit. The is found to be renormalisable at one-loop level only for integer values $\varepsilon$, a result which not yet established within $\varepsilon$-expansion. Particular attention therefore paid two interesting cases $\varepsilon=1,2$, beta functions coupling associated $i\phi^3$ $-\phi^4$ are computed. It that has asymptotic freedom four-dimensional spacetime. Some general properties Euclidean partition function $n$-point also derived.