An apparatus for generating electrical stimulation innervating patient bone marrow to reduce chemotherapy impacts on hematopoiesis, comprising: (a) a control circuit configured for receiving stimulation parameters for electrical stimulation innervating patient bone marrow to reduce chemotherapy impacts on hematopoiesis; (b) an electrode driver circuit coupled to said control circuit; (c) at least one electrode array configured for receiving drive voltage/current from said electrode driver circuit, said at least one electrode array configured for being implanted in a patient for innervating patient bone marrow; (d) wherein said control circuit is configured for converting said stimulation parameters into a series of basic building block waveforms with amplitudes, pulse width, inter-pulse delay, and stimulation frequencies according to said stimulation parameters, and outputting waveform signals, having pulse trains, each pulse train of which comprises a series of N basic building waveforms, which are output to said electrode driver circuit; (e) wherein said electrode driver circuit is configured for receiving said waveform signals from said control circuit, and for driving said at least one electrode array with a temporal pattern having single pulses and multiple pulse groups separated by inter-pulse intervals; and (f) whereby said electrical stimulation triggers nerve fibers that innervate patient bone marrow toward priming its microenvironments after chemotherapy toward reducing hematologic toxicity and mortality; wherein said control circuit, in combination with said electrode driver circuit, are configured for selectively applying electrical pulses to said at least one electrode array in a waveform consisting of: (i) a frequency from approximately 2 Hz to approximately 100 Hz; (ii) a duration of each phasic pulse of approximately 0.05 ms to approximately 3 ms; (iii) a pulse train having a stimulation on period of approximately 1 to approximately 5 seconds, at a frequency of approximately 2 Hz to approximately 100 Hz, and a stimulation off period of approximately 1 second to approximately 10 seconds; (iv) a pulse train amplitude of approximately 0.05 mA to approximately 200 mA; and (v) a stimulation duration of approximately 1 minute to approximately 90 minutes with a repeating pattern pulse train. (a) a control circuit configured for receiving stimulation parameters for electrical stimulation innervating patient bone marrow to reduce chemotherapy impacts on hematopoiesis; (b) an electrode driver circuit coupled to said control circuit; (c) at least one electrode array configured for receiving drive voltage/current from said electrode driver circuit, said at least one electrode array configured for being implanted in a patient for innervating patient bone marrow; (d) wherein said control circuit is configured for converting said stimulation parameters into a series of basic building block waveforms with amplitudes, pulse width, inter-pulse delay, and stimulation frequencies according to said stimulation parameters, and outputting waveform signals, having pulse trains, each pulse train of which comprises a series of N basic building waveforms, which are output to said electrode driver circuit; (e) wherein said electrode driver circuit is configured for receiving said waveform signals from said control circuit, and for driving said at least one electrode array with a temporal pattern having single pulses and multiple pulse groups separated by inter-pulse intervals; and (f) whereby said electrical stimulation triggers nerve fibers that innervate patient bone marrow toward priming its microenvironments after chemotherapy toward reducing hematologic toxicity and mortality; (i) a frequency from approximately 2 Hz to approximately 100 Hz; (ii) a duration of each phasic pulse of approximately 0.05 ms to approximately 3 ms; (iii) a pulse train having a stimulation on period of approximately 1 to approximately 5 seconds, at a frequency of approximately 2 Hz to approximately 100 Hz, and a stimulation off period of approximately 1 second to approximately 10 seconds; (iv) a pulse train amplitude of approximately 0.05 mA to approximately 200 mA; and (v) a stimulation duration of approximately 1 minute to approximately 90 minutes with a repeating pattern pulse train.